The central nervous system is an intricately connected network of axons and dendrites. Improper wiring of this elaborate structure during development may cause various known prenatal neurological and mental disorders. Understanding the mechanisms of axon guidance is essential for understanding these disorders also provide essential clues for the research of post-injury axonal regeneration in the mature central nervous system. Previously we have now shown that Wnt/Frizzled signaling is required for proper A-P guidance of commissural axons. Here we would like to characterize commissural axon behavior and growth cone dynamics during floor plate crossing and the subsequent anterior turning. Another aim of this proposal is to characterize aberrant commissural axons pathfinding behavior and growth cone dynamics in the presence of sFRPs or within Fz3-/- and Wnt4-/- KO spinal cords and to characterize the role of Wnt downstream signaling pathways in the anterior turn of commissural axons after floor plate crossing.